Field of the Invention
This invention relates to fingerprint sensing, especially to a capacitive fingerprint sensing apparatus and a capacitive fingerprint sensing method.
Description of the Related Art
With the developing of technology, the capacitive fingerprint sensing technology can be widely used in various kinds of electronic devices, especially portable electronic devices such as smart phones, notebook PCs and tablet PCs.
However, the fingerprint sensing technology has high resolution requirement; under the IAFIS standard, the fingerprint sensing chip should have at least resolution of 500 dpi and its unit sensing area should be 50 um*50 um. Under this condition, the capacity sensed by the unit sensing area will be small and easily interfered by the noises, so that fingerprint recognition will become harder. Therefore, the invention provides a capacitive fingerprint sensing apparatus and a capacitive fingerprint sensing method to solve the above-mentioned problems.